GB2255673A

GB2255673A - Liquid reservoir.

Info

Publication number: GB2255673A
Application number: GB9208972A
Authority: GB
Inventors: Toshihiro Nakano; Shinji Sakata
Original assignee: Aisin Seiki Co Ltd
Current assignee: Aisin Corp
Priority date: 1991-04-26
Filing date: 1992-04-24
Publication date: 1992-11-11
Anticipated expiration: 2012-04-24
Also published as: US5254815A; JPH04325362A; JP3166196B2; GB2255673B; GB9208972D0

Abstract

A liquid reservoir comprises a float movable in response to fluctuation of a volume of liquid in the reservoir; a magnet for operating a reed switch 21 secured to the float; and a reed switch unit assembly 20 comprising the reed switch 21 with a pair of terminals 24, a pair of electrical conductors 23, 23' connected to the terminals and extending from a connector casing 22, and a pair of electrical connector terminals 25 secured to the connector casing, each connector terminal 25 being electrically connected to a respective one of the conductors 23, 23'. <IMAGE>

Description

2255073 - 1 TITLE Liquid Reservoir

FIELD OF THE INVENTION

The present invention relates to a liquid reservoir for a device such as a brake master cylinder or a clutch release cylinder of a motor vehicle.

BACKGROUND ART

A conventional liquid example, in Japanese Utility Model 62(1987)-5415.

reservoir is disclosed, for Publication No.

That liquid reservoir has a bottom wall within which a transverse recess is formed. Within the recess is inserted a reed switch unit assembly having a reed switch connected in series to a power supply and a lamp. The reed switch is set to be closed by a magnet mounted on a float in the reservoir, to illuminate the lamp whenever the liquid level in the reservoir falls below a set value. In this device the reliabilitv depends on the accurate positioning of the reed switch relative to the magnet, and that accuracy is ensured by locating the reed switch in position by pawl means formed in the casing prior to fixing the reed switch in position by epoxy resin.

However, the need to form pawl means in the casing and the need to secure the reed switch by epoxy resin make the assembly of the above reservoir and reed switch cumbersome. In addition, the size of the casing should be larger than merely to accommodate the reed switch, which is contrary to the recent trend towards lightweight automotive components.

It is an object of the invention to provide a liquid reservoir with a simpler yet accurate mounting for the - 2 reed switch, and one that is less expensive to assemble.

THE INVENTION The invention provides a liquid reservoir in which a permanent magnet mounted on a float is movable to a position in proximity to a reed switch to indicate a low level of liquid in the reservoir, wherein the reed switch is incorporated in a reed switch assembly which comprises a casing, a pair of electrical connector terminals connected to the casing, a pair of electrical conductors extending from the casing and each connected to a respective one of the electrical connector terminals, and the reed switch connected between the electrical conductors.

DRAWINGS Fig. 1 is a cross-sectional view of a reservoir tank according to the present invention; and Fig. 2 is a side view with a partial cross-section ol reed switch unit assembly.

In the drawings a reservoir tank 1 in which an amount of operating fluid is stored includes a pair of spaced connecting holes 3 each of which is in the form of an extension or a projection to be connected to a respective hole (not shown) of a vehicle brake master cylinder (not shown). It is to be noted that the reservoir tank could alternatively be connected to a similar apparatus such as a clutch release cylinder. Thus, the operating fluid is set to be supplied into the master cylinder. The reservoir tank 1 has a filler opening at its top face., covered by a detachable filler cap 2.

Within the reservoir tank 1, an inner fluid chamber 5 is defined between a pair of walls of the tank 1 and a pair w 1 11 "I of partitions 4. In the fluid chamber 5, a float 6 carrying on its lower face a magnet 7 is guided for vertical movement along a shaft 11 in accordance with the liquid level of the operating fluid.

Within a bottom wall la of the reservoir tank 1, there is formed a transverse hole 10 whose axis is perpendicular to that of the shaf t 11. In the hole 10 is located a reed switch unit assembly 20 comprising a reed switch 21 to be closed when a magnetic force from the magnet 7 exceeds a set value as a result of the lowering movement thereof.

As best shown in Fig. 2, the reed switch unit assembly 20 has a connector casing 22 which is made of a-synthetic resin. The connector casing 22 includes a main body 22a provided at its right end portion with a cavity 22b with an opening 22c. A pair of parallel spaced connector blade terminals 25 is provided, each secured at its left end 25b by being embedded in the main body 22a of connector casing 22. The right end of each of the connector blade terminals 25 is positioned within the cavity 22b so as to be oriented toward the opening 22c. A sub body 22d is formed integrally with a left end of the main body 22a. The main body 22a and the sub body 22d have a common axis and the radius of the former is larger than that of the latter. The connector blade terminals 25 can be connected to a circuit comprising a power supply 20 and a warning lamp 31 in series, to indicate low liquid level in the reservoir tank 1.

A first conducting element 23 is secured at its right end to the sub body 22d so as to be electrically connected to one of the connector bl,ade terminals 25. The first conducting element 23 extends away from the sub body 22d A - and terminates in an upwardly 90-degree bent portion 23a. A second conducting element 231 is secured at its right end to the sub body 22d so as to be electrically connected to the other connector blade terminal 25. The second conducting element 231 extends away from the sub body 22d and its left end or distal end 23'a is aligned with but spaced from the distal end 23a of the first conducting element 23. The reed switch 21 with a pair of terminals each of which is in the form of a wire 24 is electrically connected by soldering between the distal end 23a of the first conducting element 23 and the aistal end 23'a of the second conducting element 23'. A pair of integral walls 23c (only one is shown) extend in the upward direction from the first conducting element 23 in such a manner that the reed switch 21 is located therebetween. In other words, a cross-section. of the resulting portion is a substantially Ushaped configuration which accommodates the reed switch 21. The walls 23c are used for protecting the longitudinal sides of the reed switch 21.

It is to be noted that the embedded left end portion 25b of the second connector blade terminal 25 is in the form of a dog-leg shape in order to prevent any longitudinal pull on the blade terminal being transmitted to the reed switch 21. An 0ring 27 mounted on the sub body 22b adjacent to the main body 22a creates a fluidtight connection between the hole 10 and the connector casing 22. A grommet 26 is provided to the connector casing 22 to make the connection waterproof.

In the illustrated embodiment the reed switch 21 rests on the first conducting element 23. However if desired the reed switch 21 can be hel:d spaced apart from the first conducting element 23 by reinforcing the strength of each Z - 5 terminal 24 of the reed switch 21.

The connections between one connector blade terminal 25 and the first conducting element 23 and between the other connector blade terminal 25 and the second conducting element 231 are established during the moulding formation of the connector casing 22.

In the present invention, the conducting elements 23 and 231 are used for the positioning of the reed switch 21, which ensures a simple structure of the reed switch unit assembly 20. Moreover, so long as a precise size of the connector casing 22 is maintained, the relative position between the magnet 7 and the reed switch 21 af ter the installation of the reed switch unit assemblv 20 in the bottom wall la of the reservoir tank 1 is substantially stable, which assures the reliability of the function of the reed switch unit assembly 20.

1

Claims

1. A liquid reservoir in which a permanent magnet mounted on a float is movable to a position in proximity to a reed switch to indicate a low level of liquid in the reservoir, wherein the reed switch is incorporated in a reed switch assembly which comprises a casing, a pair of electrical connector terminals connected to the casing, a pair of electrical conductors extending from the casing and each connected to a respective one of the electrical connector terminals, and the reed switch connected between the electrical conductors.

2. A liquid reservoir according to claim 1, wherein each electrical conductor has a proximal end embedded in the casing and electrically connected to a respective one of the connector terminals, and a distal end extending away from the casing; and the reed switch is connected between the distal end.

3. A liquid reservoir according to claim 2, wherein the distal ends of the electrical conductors are aligned on a longitudinal axis of the reed switch assembly.

4. A liquid reservoir according to any preceding claim, wherein at least one of the connector terminals has a cranked portion embedded in the casing, with the electrical connection between the respective conductor and the connector terminal being at the cranked portion and offset from the principal longitudinal axis of the connector terminal.

5. A liquid reservoir according to any preceding claim, wherein the electrical connection between the connector terminals and the respective conductors is established concurrently with the formation of the i - 7 casing.

1

6. A liquid reservoir according to any preceding claim, wherein the reed switch is positioned between a pair of side walls formed integrally with one of the electrical conductors.

7. A liquid reservoir according to claim 6, wherein the reed switch is supported by the said one of the electrical conductors.

8. A liquid reservoir according to any preceding claim, wherein the electrical conductors are wire conductors.

9. A liquid reservoir according to any preceding claim, wherein the reed switch is connected to the electrical conductors by solder.

10. A liquid reservoir according to any preceding claim, wherein the casing is formed in a stepped configuration with a smaller end receivable as a press fit in a transverse hole or recess in a floor of the reservoir.

11. A liquid reservoir substantially herein with reference to the drawings.

as described